JP2004042479A - Nozzle mechanism of injection-molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nozzle mechanism of an injection-molding machine for which a material change can be easily performed. <P>SOLUTION: This nozzle mechanism is equipped with a nozzle main body 3 which is attached to a cylinder head 2 side. The nozzle main body has a nozzle head 4 which is located at the internal front end part, and retracts when coming into contact with a die, a check pin 5 which is fixed to the internal rear end part, a valve body 6 which is longitudinally movably arranged at an internal intermediate part between the check pin and the nozzle head, a coil spring 7 which is provided between the valve body and the nozzle head and urges both of them in separating directions, and a nozzle head cover 8 which restricts the advancing position of the nozzle head. At the time of a material change, when the distal end of the check pin comes into contact with the valve port 6a of the valve body, and a sealed surface is formed, the valve body is pressed by a resin pressure and moves in the nozzle main body to the nozzle head direction, and the sealed surface with the check pin is opened. Thus, a resin channel is automatically ensured, and a molten resin can be made to flow out from the tip of the nozzle head. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an improvement in a nozzle mechanism in a plastic injection molding machine.
[0002]
[Prior art]
As a conventional nozzle mechanism of this type, for example, there is one disclosed in Japanese Patent Publication No. 44-25233.
Although not specifically shown, the conventional nozzle mechanism includes a cylinder head fixed to a heating cylinder side, a nozzle supported by the cylinder head so as to be able to move forward and backward, and a spring for urging the nozzle in a forward direction. Means, the nozzle is provided with an oblique hole communicating with the material reservoir of the cylinder head, and normally, the nozzle is urged in the forward direction by a spring means to thereby establish communication between the oblique hole and the material reservoir. When the end of the nozzle comes into contact with the mold side with the movement of the heating cylinder, the nozzle retreats against the biasing pressure of the spring means, and the oblique hole and the material pool are removed. Are connected to each other.
[0003]
Then, during the injection molding, when the tip of the nozzle comes into contact with the mold side with the movement of the heating cylinder and the oblique hole communicates with the material reservoir, the molten resin passes through the oblique hole from the material reservoir. The nozzle is injected into the mold from the tip of the nozzle hole. When the injection is completed and the heating cylinder returns to the original position, the nozzle advances again by the urging force of the spring means, and the communication between the oblique hole and the material reservoir is resumed. Is cut off.
[0004]
[Problems to be solved by the invention]
However, in the conventional nozzle mechanism, since the above-described oblique hole on the nozzle side and the material reservoir on the cylinder head side do not communicate with each other except at the time of injection, when the material is to be changed, the nozzle must be spring-loaded. There is no other method than forcibly retreating against the urging force of the means and connecting the oblique hole and the material reservoir to secure the resin flow path or remove the nozzle itself. Therefore, in the conventional nozzle mechanism, it was undeniable that the operation was particularly difficult when changing the material.
[0005]
[Means for Solving the Problems]
The present invention has been developed in order to effectively solve the problem of such a conventional nozzle mechanism, and includes a nozzle body attached to a cylinder head side, and the nozzle body is located at an inner front end thereof. A nozzle head that retreats when it comes into contact with the mold, a check pin fixed to the inner rear end, a valve body that is movable forward and backward at an internal intermediate portion between the check pin and the nozzle head, and the valve body. A coil spring provided between the nozzle head and biasing the nozzle head away from the nozzle head; and a nozzle head cover for regulating a forward position of the nozzle head. A configuration is employed in which the tip of the check pin abuts the mouth to form a seal surface.
[0006]
Therefore, according to the present invention, at the time of material change, the valve element receiving the urging force of the coil spring moves in the nozzle body toward the nozzle head by being pressed by the resin pressure, and the sealing surface with the check pin. , The resin flow path is automatically secured, and the molten resin can flow out from the tip of the nozzle head. Therefore, unlike the related art, there is no need to forcibly retract the nozzle or remove the nozzle itself from the cylinder head, so that the material changing operation can be performed very easily.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to a preferred embodiment. As shown in the drawing, a nozzle mechanism according to the embodiment has a cylindrical shape attached to a cylinder head 2 fixed to a heating cylinder 1. A nozzle body 4 which is located at an inner front end of the nozzle body 3 and retreats when contacting a mold; a check pin 5 fixed to an inner rear end; A collar-shaped valve body 6 movably disposed at an intermediate portion between the nozzle body 4 and the nozzle head 4, and a collar-shaped valve body 6 provided between the valve body 6 and the nozzle head 4 in a direction in which the two are separated from each other. The configuration includes a biasing coil spring 7 and a nozzle bed cover 8 for regulating the forward position of the nozzle head 4.
[0008]
The nozzle head 4 has a slightly larger diameter at the rear end side of the coil spring 7 that forms one of the receiving seats, and the large diameter portion is brought into contact with the nozzle bed cover 8 so that the advanced position of the nozzle head 4 can be adjusted. It is set so as to be able to retreat by δ in the nozzle body 3 when the sprue bush 9 of the mold (not shown) comes into contact with the spout.
[0009]
Further, the valve body 6 has a valve port 6a opened at the rear end side of the coil spring 7 forming the other receiving seat, and the tip of the check pin 5 is brought into contact with the valve port 6a of the valve element 6. Thereby, it is set so that a seal surface can be formed between the valve port 6a of the valve body 6 and the tip of the check pin 5. In the figure, reference numeral 10 denotes a sealing material provided at a place where the nozzle body 3 and the cylinder head 2 are attached.
[0010]
Therefore, under the nozzle mechanism according to the present embodiment, when the tip of the nozzle head 4 comes into contact with the sprue bush 9 on the mold side with the movement of the heating cylinder 1 during injection, the nozzle head 4 Will recede in the nozzle body 3 by δ against the urging force of the coil spring 7. In such a state, the molten resin pressure in the material pool on the cylinder head 2 side As shown in FIG. 1, the valve body 6 is pushed in the direction of the nozzle head 4 against the urging force of the coil spring 7 to overcome the urging pressure, and a seal formed between the valve pin 6 and the tip of the check pin 5 is formed. Release the surface. Accordingly, the resin flow path is secured, whereby the molten resin is injected into the mold from the nozzle hole 4a of the nozzle head 4 through the inside of the valve body 6.
[0011]
Then, when the injection is completed and the heating cylinder 1 returns to the original position at the time of measurement, as shown in FIG. 2, the nozzle head 4 is pushed to the forward position regulated by the urging force of the coil spring 7 as shown in FIG. At the same time, the valve element 6 is also pushed in the direction of the check pin 5 by the urging force of the coil spring 7 so that its valve port 6a abuts on the tip of the check pin 5 to completely shut off the resin flow path.
[0012]
In this case, since the operating area in which the nozzle head 4 advances by δ is set, if the inner diameter of the nozzle body 3 is D, the internal volume at the front end side of the nozzle body 3 is πD ^By increasing the pressure by 2/4 × δ and reducing the internal pressure at the front end side of the nozzle body 3, it becomes possible to absorb the resin for the thermal expansion, so that the resin leakage from the nozzle head 4 side is also effective. Can be prevented.
[0013]
Also, at the time of material change, as shown in FIG. 3, the nozzle head 4 itself is pushed to the forward position regulated by the urging force of the coil spring 7, as in the case of the metering. Since the molten resin pressure in the material pool on the side of the cylinder head 2 overcomes the urging pressure of the coil spring 7, the valve body 6 is again pushed in the direction of the nozzle head 4 against the urging force of the coil spring 7, and the check pin Then, the sealing surface formed between the front end portion 5 and the front end portion is opened.
[0014]
Accordingly, the resin flow path is secured, so that the molten resin automatically flows out of the nozzle hole 4a of the nozzle head 4 to the outside through the inside of the valve body 6, and a new resin flows into the heating cylinder. 1 will flow. As a result, in the present embodiment, as in the conventional case, there is no need to forcibly retract the nozzle or to remove the nozzle itself from the cylinder head, so that the material change operation can be performed very easily. It becomes.
[0015]
【The invention's effect】
As described above, according to the present invention, by adopting the above configuration, at the time of material change, the valve element receiving the urging force of the coil spring moves in the nozzle body toward the nozzle head by being pressed by the resin pressure, Since the sealing surface with the check pin is opened, the resin flow path is automatically secured, and the molten resin can flow out from the tip of the nozzle head. Therefore, unlike the related art, there is no need to forcibly retract the nozzle or remove the nozzle itself from the cylinder head, so that the material changing operation can be performed very easily.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part showing a state of a nozzle mechanism according to an embodiment of the present invention at the time of injection.
FIG. 2 is a sectional view of a main part showing a state at the time of the weighing.
FIG. 3 is a sectional view of a main part showing a state at the time of material replacement.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Heating cylinder 2 Cylinder head 3 Nozzle body 4 Nozzle head 4a Nozzle hole 5 Check pin 6 Valve element 6a Valve port 7 Coil spring 8 Nozzle head cover 9 Sprue bush 10 Seal material

Claims (1)

A nozzle body attached to the cylinder head side, the nozzle body is located at an inner front end thereof and retreats when it comes into contact with a mold; a check pin fixed to the inner rear end; A valve body disposed at an intermediate portion between the nozzle heads so as to be able to advance and retreat, a coil spring provided between the valve body and the nozzle head for urging the two in a direction to separate them, and advancing the nozzle head A nozzle head cover for regulating the position, wherein the valve body is pressed by a coil spring, and the tip of a check pin abuts on the valve port to form a seal surface, the nozzle of the injection molding machine. mechanism.

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